Valve for fuel injection pumps



Sept 10. 1940. vH. C. EDWARDS 2,214,364

VALVE FOR FUEL INJECTION PUMPS Filed Dec. 1s. 193:1 2 sheets-sheet 2Parenteel Sept. 1o, 194e UNITED STATESv PATENT OFFICE 2,214,364 VALVEFoa FUEL mmcnon Puurs Application December 16, 1937,*Serial No 180,122

6Claims.

This invention relates to a valve for pumps l for the fuel injectionsystems of compression ignition engines, particularly pumps of the typethat terminate the delivery of fuel to the injection nozzle by relievingthe pressure in the pump chamber during the pressure stroke'of thepiston. The principal object of the present invention is to devise adelivery valve for the above type of pump which upon relief of thepressure in the pump chamber, will permit a return flow thereto of fuelin the conduit leading to the injection nozzle, thereby relieving thepressure in said conduit and thus preventing leakage or dribble of fuelfrom said nozzle. Other objects are simplicity and cheapness ofconstruction and compactness of design. `'I'he invention consists in theconstruction, combinations and arrangements of parts hereinafterdescribed and claimed.

In the accompanying drawings, which form part of this specification, andwherein like symbols refer to like parts wherever they occur,

Fig. 1 is a central longitudinal section through a fuel injection pumpprovided with a delivery valve embodying my invention,

Fig. 2 is an enlarged central longitudinal section through said pump inthe region of the discharge valve;

Fig. 3 is a section similar to Fig. 2 illustrating a modification of theinvention; and Figs. 4 and 5 are views similarto Figs. 1 and 2,respectively, illustrating a further modication of the invention.

In. the accompanying drawings, my invention is shown in connection witha pump of the kind used for supplying .fuel to the injection nozzle of'aninternal combustion engine of thev comxpression ignition type. 'l'.heupper portion of the pump body or housing l has a vertical bore thereinin which is mounted a cylinder 2 having a head portion 3 supported on anannular seat 4 provided therefor in said bore. The pump cylinder 2 isheld down on its seat in the pump housing bore by an outlet fitting 5that is threaded into the upper end of said bore and has its upper endthreaded for connection with a suitable conduit or pipe (not shown)which leads to a hydraulically operated fuel injection nozzle (notshown) for delivering fuel to the combustion chamber of the engine.''l'.'he outlet fitting 5 is provided near its lower end with aperipheral groove 6 adapted to receive and support a com'- pressiblegasket 1 that is held under compression between said groove and the wallof the housing bore and prevents leakage of primary fuel past saidfitting.

Mounted for 'reciprocating .movement in the pump cylinder or barrel 2 isa piston 8 which cooperates with said cylinder to form a pressure spaceor chamber 3 therein at the upper end thereof. vThe pump cylinder y2 hasa radial fuel I l port l therein adapted to establish communica- V tionbetween the pressure space 9 and ar fuel chamber or passageway I I inthe pump housing; and the piston 8 is provided with an annular groove I2which communicates with said presl0 sure space through a longitudinalperipheral groove i3 in said'piston.

Clamped between the outer marginal portions of the opposing end facesofthe pump cylinder 2 and the outlet fitting 5 is an annular spacer Ilor washer I4. Located in the opening in the washer Il is a discharge.valve l preferably in the form of a exible or resilient disk of metalor other suitable material, which is of smaller diameter than saidopening so as to provide an annular space or passageway i6 forfuelbetween said washer and said disk. This disk has a relatively thickrim or marginal portion I1, which seats on the upper end of the cylinder2, and a relatively thin middle or body portion I8' that 25 covers theupper end of the piston receiving bore in the cylinder 2 and forms thetop wall of the pressure space l and is provided with a central circularfuel opening or port I9 adapted to be closed by the adjacent end of theoutlet tting 5. so

The valve opposing end of the outlet fitting 5 has an annular groovetherein which limits the contact between said end of said fitting andthe valve l5 to the ported central portion of the latter and also formsan annular fuel passageway or chamber 2l above said valve that communi-Acates at its outer margin'with the annular fuel passageway It betweensaid valve and the spacing washer I4. The outlet fitting 5 is alsoprovided with a fuel passageway 2l which leads from 40 the annularchamber 20 to the outer end of said fitting and communicates with andconstitutes a part of the supply pipe or conduit for the injectionnozzle of the fuel injection system. The

spacing washer IA is preferably made slightly thinner than the rimportion I1 of the disch:- :ge

valve, whereby the ported-central portion a of said valve is dished orbowed downwardly by the middle portion of the outlet fitting I and isplaced under tension sumcient to remain in contact with said tting andkeep the port I9 closed during thesuction stroke of the piston.

The modified construction shown in Fig. 3 is similar to that shown inFig. 2, except that the resilient discharge valve of Fig. 3 is made upof a plurality of superimposed disks I5a of resilient metal and issupported clear of the upper stroke'of the plunger, the central portionI8 of the discharge valve I5 is pressed tightly against the outletfitting 5, thereby preventing escape of fuel through the port I9 in saidvalve, while the rim portion I1 of said valve is lifted olf its seat onthe upper end of the cylinder, thereby permitting the fuel to passthrough the annular space I6 between said rim and the spacing washer Iland thence into the annular chamber 20 above said valve and thencethrough the longitudinal passageway 2l leading to the fuel injectionnozzie. At a. predetermined point in the pressure stroke of the piston,the annular groove I2 therein is placed in communication with the port Iin the cylinder, thereby relieving the pressure in the pump chamber andon the rim portion I'I of the valve, which portion is then forced downon its seat on said cylinder by the greater pressure in the annularchamber 20. This higher pressure of the fuel in the annular chamber andthe conduit leading to the closed injection nozzle then operates toforce the resilient middle portion I8 of the discharge valve downwardlyoiI its seat on the inner end of the outlet fitting, thereby permittinga return flow of fuel from said conduit through the central port I9 insaid valve into the pressure space of the cylinder. 'I'his return flowof the fuel reduces the pressure of the fuel in the delivery conduit toa pressure that will enable the injection nozzle to close quickly andtightly and thus prevent dripping or dribbling of fuel therefrom andthereby elimi-l nate preignition or after burning of the fuel in thecombustion chamber of the engine.

In the modification shown in Figs. 4 and 5, the outlet fitting 5a has anaxial fuel passageway 2Ia, threads that terminate Yshort of the outerend of the housing bore and a peripheral groove 6a located outwardly ofits threads and adapted to receive a compressible gasket 1a. Thislocation of the gasket 1a. outwardly of the threaded portion of thehousing bore makes it unnecessary to force the gasket through thethreaded portion o'f the bore and thus prevents the gasket from beingtorn or frayed by said threads.

The discharge valve I5c shown in Figs. 4 and 5 is supported in anannular casing located in I the housing bore between the pumpv cylinder2 and the outlet fitting 5a. 'I'his casing comprises a rim portion 22,which is clamped between the outlet fitting and the cylinder, and a hubportion 23, which is connected to said rim portion 'by a radial webhaving openings 2l therein.- The valve I5c, which is preferably made upof a series of superimposed disks of resilient metal, has its centralportion seated on the upper or outer end of the hub portion 23 of theannular valve casing and provided with a central port I9a of smallerdiameter than the diameterof said hub portion.v

The valve Ais loosely secured to the valve casing by means of a headedpin 25, which extends through the port I9a with an annular clearancespace therebetween and is threaded or otherwise setion 23. The valve isof smaller diameter than the inner diameter of the rim portion 22 of thevalve casing so as to provide an annular space therebetween; and themarginal portion of said valve is adapted to seat flatwise against thelower or inner end of the outlet'fitting 5a around the adjacent epd ofthe fuel passageway 2Ia` therein.

The operation of the modified valve construction shown in Figs. 4 and 5is as follows: 'Ihe fuel drawn into thevpressure space or chamber 9during the suction stroke of the piston 8 is placed under pressure whensaid piston during its pressure stroke passes the port I0. During thispressure stroke of the plunger, the pressure of the fuel against theunderside of the valve lifts the ported central portion thereof oil' itsseat on the upper end of the hub .portion 23 of the valve casing,thereby permitting the fuel to pass through the axial port IBa in saidvalve and thence into the axial fuel passageway 2Ia in the outlet tting.When the annular groove I2 in the piston registers -with the port III inthe cylinder, the pressure of the fuel on the underside of the valve isrelieved and the higher pressure of the fuel in the fuel passageway 2 Iaon the upper surface of the valve then operates to force the marginalportion of said valve off its seat at the inner end of the outletfitting, thereby permitting a return flow of fuel from said yfuelpassageway into the pressure chamber of the cylinder. This return flowof the fuel reduces the pressure of the fuel in the delivery conduit,thereby enabling the hydraulically opened injection nozzle suppliedthereby to close quickly and tightly and thus prevent dripping ordribbling of fuel therefrom.

Obviously, the hereinbefore described construction admits ofconsiderable modification without departing from the invention.Therefore, -I do not wish to be limited to the precise constructionsshown and described.

What I claim is:

[1. A valve construction comprising an inlet chamber, an outlet chamber,valve seats associated with the adjacent ends of said chambers, theinlet chamber valve seat facing the outlet chamber and the outletchamber valve seat facing the inlet chamber, and a disk valve interposedbetween said endsof said chambers and having a central ported portion,`the marginal portion of one face of said valve and the central portedportion of the opposite face thereof being adapted to seatsimultaneously on said inlet and outlet chamber, respectively, to cutolf communication therebetween, said valve beingy flexible whereby oneof said marginal and central ported portions of said valve is adapted tobe forced off its seat by a pressure in said inlet chamber, in excess ofthat in said outlet chamber, and

the other of said portions is adapted to be forced:A

pff its seat by a. pressure in said outlet chamber greater than thepressure in said inlet chamber.

2. A valve construction comprising an inlet chamber, an outlet chamber,valve seats associated withthe adjacent ends of said chambers, the inletchamber valve seat facing the outlet chamber and the outlet chambervalve seat facingthe inlet chamber, and a. disk valve interposed betweensaid ends of said chambers and havingA a central ported portion', themarginal portion of one face of said valve and the central portedportion of the opposite face thereof being adapted to seatsimultaneously one on said inlet chamber and the other on said outletchamber to cut olI communication therebetween, said valve cured to theupper or outer end of the hub por being flexible whereby one of saidmarginal and u ciated with the adjacent ends ofv said chambers,

the inlet chamber valve seat facing the outlet chamber and the outletchamber valve seat facing the inlet chamber, and a disk valve interposedbetween said ends of said chambers and having a central ported portion,the marginal' portion of one face of said valve and the central portedportion of the opposite face thereof being adapted to seatsimultaneously one on said inlet chamber and the other on said outletchamber to cut olf communication therebetween, said valve being flexiblewhereby said marginal portion of said valve is adapted to be forcedoiits seat by a pressure in said inlet chamber in excess of that in saidoutlet chamber, and said centra-l ported portion is adapted to be forcedoi its seat by a pressure in said outlet chamber greater than .thepressure in said inlet chamber.

4. A valve construction comprising an inlet chamber, an outlet chamber,valve seats associated with the adjacent ends of said chambers, theinlet chamber valve seat facing the outlet chamber and the outletchamber valve seat facing the inlet chamber, and a disk valve interposedbetween said ends of said chambers and having'a central ported portion,the marginal portion of one face of said valve and the central portedportion of the opposite face thereof being adapted to seatsimultaneously one. on said inlet chamber and the other on said outletchamber to cut off communication therebetween, said valve being flexiblewhereby said central ported portion of said valve is adapted to beforced .o its seat by a pressure in said inlet chamber in excess of thatin said outlet chamber, and said marginal portion is adapted to beforced off its seat by a pressure in said outlet chamber greater thanthe pressure in said inlet chamber.

5. A valve construction comprising an inlet 'posed between said ends ofsaid chambers and having a central ported portion, the marginal portionof one face Vof said valve and the central ported portion of theopposite face thereof being adapted to seat simultaneously one on saidinlet chamber and the other on said outlet chamber to cut offcommunication therebetween, said valve comprising a plurality ofsuperimposed disks having registering openings forming said centralported portion of said valve, said disks being flexible whereby one ofsaid marginal and central ported portions of said valve is adapted tobe` forced oi its seat by a pressure in said inlet chamber in excess ofthat in said outlet chamber, and the other of said portions is adaptedto be forced off its seat by a pressure in said outlet chamber greaterthan the pressure in said inlet chamber. p

-6. A valve construction comprising an inlet chamber, an outlet chamber,valve seats associated with the adjacent ends of said chambers, theinlet chamber valve seat facing the outlet chamber and the outletchamber valve seat facing the inlet chamber, a disk valve interposedbetween said ends of said chambers and having a central ported portion,the marginal portion of' 'one face of said valve and the central portedportion of the opposite face thereof being adapted to seatsimultaneously on said 'outlet and inlet chamber, respectively, to cutoi ycommunication therebetween and means for loosely securing saidcentral ported'portion o! said valve to the valve seat for said centralported portion, said valve being flexible whereby the loosely securedcentral ported portion of said'- valve is adapted yto be forced off itsseat by a pressure invsaid inlet chamber in excess of that in saidoutlet chamber, and said marginal portion of said valve is adapted to beforced oi! its seat by a pressure in said outlet chamber greater thanthe pressure in said inlet chamber.

HERBERT C. EDWARDS.

